Catheter system with linear actuation control mechanism

ABSTRACT

The present teachings provide a delivery catheter with a deflectable tip and the deflection angle of the deflectable tip can be accurately controlled. Specifically, the delivery catheter includes a deflectable distal tip operably coupled to a pull wire, an elongated catheter portion, and a control mechanism. The control mechanism is configured to activate a rapid transformation of the deflectable tip from its linear profile to its curved profile. The control mechanism further includes a linear actuation mechanism. Such linear actuation mechanism converts a rotation motion of the control mechanism to a precise linear motion, which in turn accurately controls the bend angle of the deflectable tip of the delivery catheter. Such control mechanism can be used in applications that require the control of the distal deflection of the catheter, such as EP catheter, trans-septal device, and other devices.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is based on and claims priority to U.S. ProvisionalPatent Application 62/486,956, filed Apr. 18, 2017, the entire contentsof which is incorporated by reference herein as if expressly set forthin its respective entirety herein.

TECHNICAL FIELD

The present teachings generally relate to a delivery catheter with adeflectable distal portion. In one aspect, the delivery catheter caninclude a control mechanism for precisely controlling the deflectingangle of the distal portion of the delivery catheter.

BACKGROUND

Deflectable catheters usually feature a tip that can be pulled into adefined curve. This deflection of the catheter tip is independent of therest of the catheter. Such movement can be achieved by exerting a forcebiased to one side of the distal portion by using a wire connected to apull or anchor ring near the tip. The catheter tip can return to itsoriginal shape when the force is reduced or removed.

Deflectable catheters have been used in cardiology, peripheral vasculartherapies, structural heart therapies, and many other fields thatrequire the catheter tip to make angulated turns or to be fairlyaccurately positioned in an anatomy. Examples include guiding catheters,implant delivery systems, or EP mapping catheters, and ablationcatheters.

The deflectable catheters in the market include uni-directionalcatheter, bi-directional catheters, 4-way deflectable catheters, andomni-directional catheters. A bi-directional catheter features a tipthat can be pulled in two directions (often opposite from each other).This can be achieved by using two pull wires connected to a distal pullring. A 4-way deflectable catheter can be pulled in 4 directions. The4-way deflectable catheter often requires four wires connected to adistal pull ring. An omni-directional catheter is a 4-way deflectablecatheter that is often remotely controlled by a robotic device to allowthe tip to be deflected in any direction. Deflection is achieved bymanipulating one or more of the pull wires simultaneously. Roboticcatheters can be used for a variety of applications and provide thephysician with a greater control and less exposure to radiation.

The deflectability of the catheter tip can be qualified in many ways. A“curve angle” is measured as the angle of the tip movement relative toits straight axis, i.e. the bend angle. The term “bend radius” refers tothe inside curvature of the catheter and indicates the minimum radiusone can bend a catheter without kinking it. Most deflectable cathetershave a curve angle ranging between about 45 and about 180 degreesdepending on the application, but can be up to about 270 degrees or insome instances 360 degrees. A “curve diameter” indicates the furthestdistance that the catheter moves from its straight axis as it is beingdeflected. The “reach” measures the displacement of the tip from itscentral or straight axis.

Deflectable catheters also are categorized as single plane deflectioncatheters and bi-plane deflection catheters. A single plane deflectioncatheter deflects within a single plane and includes all uni-directionalcatheters and most bi-directional catheters. The tip of a bi-planedeflection catheter can deflect along X and Y axis. In other words, itturns side to side and forwards or backwards. Bi-plane deflectioncatheters include 4-way deflectable catheters.

The deflection of the catheter tip is typically achieved by one or morepull wires via a control mechanism. The most common control mechanism isa simple push-pull mechanism that extends or retracts the pull wire andthereby actuates the deflection of the catheter tip. Thus, the relativelinear motion of the push-pull mechanism decides the bend angle andcontrol the planarity of the catheter tip. Although easy to operate, thelinear motion of the push/pull mechanism lacks the ability to preciselycontrol the bend angle. In percutaneous applications, the curve angle ofa deflectable tip needs to be able to be meticulously adjusted in orderfor a clinician to find a desired location inside each individualanatomy. Thus, the lack of the ability to be finely adjusted must beimproved to allow a clinician to better treat patients.

SUMMARY

One aspect of the present teachings provides a catheter assembly thatcomprises a catheter shaft and a control mechanism. The catheter shafthas a deflectable distal portion. The control mechanism is configured toactivate a rapid transformation of the deflectable distal portion of thecatheter shaft from a linear profile to a curved profile. The controlmechanism further comprises a linear actuation mechanism. The linearactuation mechanism converts a rotation motion of the control mechanismto a precise linear motion. The linear motion of the control mechanismis configured to control the bend angle of the deflectable distalportion of the catheter shaft.

Another aspect of the present teachings provides a catheter assemblythat comprises a catheter shaft, a pull wire joining the distal end ofthe catheter shaft, and a control mechanism. The pull wire is configuredto deflect a distal portion of the catheter shaft. The control mechanismincludes a compression tube mount, and a pull wire mount. A proximalportion of the catheter shaft joins the compression tube mount. Aproximal end of the pull wire joins the pull wire mount. A change indistance between the pull wire mount and the compression tube mountresults the deflection of the distal portion of the catheter shaft.

Another aspect of the present teachings provides a control mechanismcomprising an outer handle shaft, a middle handle shaft. The middlehandle shaft is positioned inside an interior lumen of the outer handleshaft. The middle handle shaft has a first position wherein the middlehandle shaft engages an interior surface of the outer handle shaft via athread engagement, and a second position wherein the middle handle moveslaterally without the restriction of the thread engagement.

Another aspect of the present teachings provides a control mechanismhaving a linear actuator. The linear actuator comprises a threadedrotator and a thread follower with pairing threads. The linear actuatoris configured to convert the rotational motion of the threads into arelative linear motion of the middle handle and the outer handle shaft.

Another aspect of the present teachings provides a control assemblyhaving the middle handle shaft automatically centers within the outerhandle shaft by two centering springs. Each centering spring is placedon each side of the middle handle shaft. When the centering spring is inits relaxed state, the middle handle shaft in centered within theinterior lumen of the outer handle shaft.

Another aspect of the present teachings provides the middle handle shafthaving a thread engagement mechanism. The thread engagement mechanismcomprises a thread follower that engages a thread inside the interiorluminal surface of the outer handle shaft. The thread engagementmechanism further comprises a spring. When the spring is compressed, thethread follower engages the thread inside the interior luminal surfaceof the outer handle shaft. When the spring relaxes, the thread followerdisengages from the threads inside the interior luminal surface of theouter handle shaft.

Another aspect of the present teachings provides a catheter assemblythat comprises a catheter shaft and a control mechanism. The cathetershaft comprises a first configuration where a distal portion aligns withthe longitudinal axis of the catheter shaft, and a second configurationwhere the distal portion curves away from the longitudinal axis of thecatheter shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the present teachingswhere a delivery catheter assembly including a control handle assemblyand a catheter shaft with a deflectable distal portion.

FIGS. 2A-2B are perspective views of a distal portion of the cathetershaft, according to one embodiment of the present teaching.

FIG. 2C is a perspective view of a control handle assembly, according toone embodiment of the present teaching.

FIGS. 3A-3D are perspective views of a control handle assembly,according to one embodiment of the present teaching.

FIGS. 4A-4D are perspective views of a delivery catheter assemblyincluding a control handle assembly and a catheter shaft with adeflectable distal portion at various operating stage, according to oneembodiment of the present teaching.

FIGS. 5A-5E are perspective views of a control handle assembly atvarious operating stage, according to one embodiment of the presentteaching.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Certain specific details are set forth in the following description andfigures to provide an understanding of various embodiments of thepresent teachings. Those of ordinary skill in the relevant art wouldunderstand that they can practice other embodiments of the presentteachings without one or more of the details described herein. Thus, itis not the intention of the applicant(s) to restrict or in any way limitthe scope of the appended claims to such details. While variousprocesses are described with reference to steps and sequences in thefollowing disclosure, the steps and sequences of steps should not betaken as required to practice all embodiments of the present teachings.

As used herein, the term “lumen” means a canal, a duct, or a generallytubular space or cavity in the body of a subject, including a vein, anartery, a blood vessel, a capillary, an intestine, and the like. Theterm “lumen” can also refer to a tubular space in a catheter, a sheath,a hollow needle, a tube, or the like.

As used herein, the term “proximal” shall mean close to the operator(less into the body) and “distal” shall mean away from the operator(further into the body). In positioning a medical device inside apatient, “distal” refers to the direction relatively away from acatheter insertion location and “proximal” refers to the directionrelatively close to the insertion location.

As used herein, the term “wire” can be a strand, a cord, a fiber, ayarn, a filament, a cable, a thread, or the like, and these terms may beused interchangeably.

As used herein, the term “sheath” may also be described as a “catheter”and, thus, these terms can be used interchangeably.

Unless otherwise specified, all numbers expressing quantities,measurements, and other properties or parameters used in thespecification and claims are to be understood as being modified in allinstances by the term “about.” Accordingly, unless otherwise indicated,it should be understood that the numerical parameters set forth in thefollowing specification and appended claims are approximations. At thevery least and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, numerical parametersshould be read in light of the number of reported significant digits andthe application of ordinary rounding techniques.

The present teachings relate to an implant delivery catheter with adeflectable catheter tip, an ablation catheter with a deflectable tip orany therapy catheter requiring actuation at the distal section or tip.In some embodiments, the delivery catheter includes a control mechanism.In some embodiments, the control mechanism is a precision controlmechanism. In certain embodiments, the control mechanism allows aclinician to control, sometimes accurately, the bend angle, reach andcurve diameter of the deflectable tip.

Referring now to FIG. 1, according to one embodiment of the presentteachings, the delivery catheter assembly (10) includes a catheter shaft(12) having a distal portion (22), where the distal portion of thecatheter shaft (12) is deflectable, and a control handle assembly (14)disposed at the proximal portion (26) of the catheter shaft (12). Insome embodiments, the control handle assembly (14) is connected with theproximal portion (26) of the catheter shaft (12). In some embodiments,the control handle assembly (14) includes a pull wire (16). In someembodiments, the pull wire (16) extends along the longitudinal axis ofthe catheter shaft (12). In some embodiments, the pull wire (16)connects its distal end (34) to the distal end (24) of the cathetershaft (12) and connects the control handle assembly (14) at the proximalend (38). In some embodiments, when a clinician applies tension on theproximal end (38) of a pull wire (16), such tension is transferred tothe distal end (34) of the pull wire (16) and through the distal end(34) of the pull wire (16) that is connected with the distal end (24) ofthe catheter shaft (12). As a result, the catheter shaft (12)articulates in a single direction. In some embodiment, the pull wire(16) is positioned inside a peripheral lumen (18) extending along thecatheter shaft (12). In some embodiments, the direction of thearticulation is defined by the positions of the pull wire (16), or theperipheral lumen (18) that housing the pull wire (16), in reference tothe center axis of the catheter shaft (12).

According to some embodiments, a catheter shaft (12) of the presentteachings include a longitudinal axis that runs from its proximal end(28) to its distal end (24). In some embodiments, the catheter shaft(12) includes a central longitudinal lumen (40). In some embodiments,the central longitudinal lumen (40) allows an implant, including a RFwire or other devices, to slide through. In some embodiments, thecatheter shaft (12) includes an elongated and generally flexible portion(42) and an articulable distal portion (22). In some embodiments, thearticulable distal portion (22) is configured to bend, curve, orotherwise change its shape and position. In some embodiments, thearticulation of the distal portion (22) is triggered by the controlhandle assembly (14).

FIGS. 2A-2B illustrate one embodiment of the articulable distal portion(22). As shown in FIG. 2A, the pull wire (16) runs inside a peripherallumen (18) exterior to the central longitudinal lumen (40) of thecatheter shaft (12) along the length of the articulable distal portion(22) of the catheter shaft (12). The pull wire (16) attaches to thedistal end (24) of the catheter shaft (12) by an attaching means. Insome embodiments, the attaching means is a ring at the distal tip of thecatheter shaft (12) to which the pull wire (16) is soldered. In someembodiments, the attaching means includes the pull wire (16) beingembedded in the composite plastic or polymer material at the tip of thecatheter shaft (12). In some embodiments, the pull wire (16) embedded ina composite of plastic or polymer are coiled at the attaching location,for example, to provide a strong attachment and to prevent the pull wire(16) from being pulled out of the composite material when tension isapplied. As the tension is applied to the pull wire (16), the distalportion (22) of the catheter shaft (12) articulates in a singledirection as shown in FIG. 2B.

According to some embodiments of the present teachings, both thegenerally flexible portion (42) and an articulable distal portion (22)of the catheter shaft (12) have a bending stiffness that allows thecatheter (12) to be trans-luminally positioned through a tortuous pathinto the heart. According to some embodiments of the present teachings,the bending stiffness of the articulable distal portion (22) of thedelivery catheter (12) is substantially less than the generally flexibleportion (42) of the catheter shaft (12). In some embodiments, thecatheter shaft (12) has sufficient column strength to remainsubstantially un-deflected when the pull wire (16) is tensioned. In someembodiments, the articulable distal portion (22) of the deliverycatheter (12) is sufficiently flexible for deflection into a curvature.

In some embodiments, a middle portion (35) of the pull wire (16) isdisposed within a peripheral lumen (18) unattached to the catheter shaft(12). The proximal end (38) of the pull wire (16) can be attached to thecontrol handle assembly (14) as shown in FIG. 1. A proximal portion (26)of the catheter shaft (12) can be connected to the control handleassembly (14). According to one embodiment of the present teachings, thecontrol handle assembly (14) is configured to apply an axial motion tomanipulate the pull wire (16). In some embodiments, the manipulation ofthe pull wire (16) results in deflecting the distal portion (22) of thecatheter shaft (12).

FIG. 2C illustrates the proximal end portion (36) of the pull wire (16)and the catheter shaft (12). As shown in FIG. 2C, the proximal end (38)of the pull wire (16) is fixed to a pull wire mount (160). The proximalportion (26) of the catheter shaft (12) is fixed to a compression tubemount (150). The proximal end (28) of the catheter shaft (12) furtherextends proximally beyond the control handle assembly (14). The relativemovement of the compression tube mount (150) and pull wire mount (160)will be translated to a relative motion between the catheter shaft (12)and pull wire (16), and thereby deflects the distal portion (22) of thecatheter shaft (12).

FIG. 3A illustrates an exploded view of the control handle assembly(14). FIG. 3B illustrates an assembled view of the control handleassembly (14). Now referring FIG. 3A, the control handle assembly (14)includes an elongated hollow outer handle shaft (100). In someembodiments, a hollow middle handle shaft (110) is disposed within theelongated hollow outer handle shaft (100). The distal end (102) of theouter handle shaft (100) is sized to allow a threaded rotator (140) toextend through, while block the middle handle shaft (110) in the outerhandle shaft (100) from sliding proximally out. The proximal end (104)of the outer handle shaft (100) is sized to allow a catheter shaft (12)to extend through, while also blocking the middle handle shaft (110)from sliding distally out. The outer handle shaft (100) further has acenter lumen (106) and a through hole (108) that extends from the centerlumen (106) radially to the exterior surface (101) of the outer handleshaft (100). In some embodiments, the size of the through hole (108) isconfigured to house a set screw (120). In some embodiments, the locationof the through hole (108) could vary along the outer handle shaft (100),so long as it centers over the thread follower (122) when the middlehandle shaft (110) centers within the outer handle shaft (100). In someembodiments, a longitudinal slot is designed to allow a first ballbearing (127) to slide within. According to this embodiment, thelongitudinal slot is placed on the interior surface (103) of the centerlumen (106) starts near the through hole (108) and extends distally tothe distal end (102) of the outer handle shaft (100).

FIG. 3A further illustrates an elongated middle handle shaft (110)having a center lumen (116) extending from its distal end (112) to itsproximal end (114). The middle handle shaft (110) further includes athread follower retainer slot (118). Similar to the through hole (108),the placement of the thread follower retainer slot (118) could vary solong as it allows the thread follower (122) centers under the set screw(120) when the middle handle shaft (110) centers within the outer handleshaft (100). The thread follower retainer slot (118) is designed toreceive a thread follower (122). The center lumen (116) of the middlehandle shaft (110) is sized to receive a threaded rotator (140), acompression tube mount (150), and a pull wire mount (160).

Continue referring to FIG. 3A, the thread follower (122) has a top side(121) and a bottom side (123). The bottom side (123) of the threadfollower (122) has threads (124) configured to match the threads (144)of the threaded rotator (140). The thread follower (122) furtherincludes a hole (126) for holding a first ball bearing (127) followed bya spring (128) in the middle and a second ball bearing (129). In someembodiment, the all ball bearings (127, 129) and the spring (128) aresized to be housed inside the hole (126), while the spring (128) istrapped in between the two ball bearings (127, 129) as shown in FIG. 3B.In some embodiment, when the middle handle shaft (110) is centeredinside the outer handle shaft (100), the first ball bearing (127) isthen resume its position and engages under the set screw (120). The setscrew (120) then compresses the first ball bearing (127) downward. Thefirst ball bearing (127) in turn compresses the spring (128) and therebyalso pushes the thread follower (122) downward. In another embodiment,as the first ball bearing (127) moves away from its position under theset screw (120), the spring (128) relaxes and thereby allows the threadfollower (122) moving upward.

Continue referring to FIG. 3A, a threaded rotator (140), a compressiontube mount (150), and a pull wire mount (160) are placed inside thecenter lumen (116) of the middle handle shaft (110). In someembodiments, the threaded rotator (140), the compression tube mount(150), and the pull wire mount (160) are arranged from the distal end(112) to the proximal end (114) of the middle handle shaft (110). Insome embodiments, the threaded rotator (140) has an elongated hollowbody with a threaded proximal portion (144) and an unthreaded distalportion (142). As shown in FIG. 3A, the distal portion (142) extendsfrom inside the middle handle shaft (110) and outer handle shaft (100)distally to the outside. In some embodiments, a steering knob (149)attaches to the distal portion (142) of the threaded rotator (140) thatis outside of the outer/middle handle shafts (100, 110). In someembodiments, the proximal end (146) of the threaded rotator (140) isdisposed next to a compression tube mount (150). In some embodiments,the threaded rotator (140) has a longitudinal lumen (141) configured toreceive a catheter shaft (12).

FIG. 3A illustrates a compression tube mount (150) is positionedproximal to the threaded rotator (140). In some embodiments, thecompression tube mount (150) has an elongated hollow body with an axiallumen (156) extending from one end (152) to the other end (154). Thedistal end (152) of the compression tube mount (150) butts against theproximal end (146) of the threaded rotator (140). In some embodiment,the threaded rotator (140) and the compression tube (150) are configuredto move laterally together, while the threaded rotator (140) rotatesindependently from the compression tube mount (150). According to oneembodiment of the present teaching, as the threaded rotator (140)rotates against the thread follower (122), the threaded rotator (140)also moves laterally, and the compression tube mount (150) moveslaterally along with the threaded rotator (140). In some embodiment,such threaded rotator (140) and compression tube (150) assemblyconfiguration can be achieved by many means known to those skilled inthe art. For example, a first end cap could be used to stop proximalmotion of the threaded proximal portion (144) of the threaded rotator(140), and a second end cap could be used to stop distal motion of theproximal end (154) of the compression tube mount (150). [need to bereviewed]

Continue referring to FIG. 3A, the compression tube mount (150) has akey slot (158) extending from its axial lumen (156) radially away to theexterior surface. The key slot (158) is configured to receive a key onthe catheter shaft (12). Through this key slot-key assembly, thecatheter shaft (12) is bonded to the compression tube mount (150). Suchbonding assembly prevents the catheter shaft (12) from rotating andmoving laterally relative to the compression tube mount (150). In someembodiments, key slot-key assembly allows the lateral movement of thethreaded rotator (140) and compression tube (150) assembly beingtranslated to the catheter shaft (12).

FIG. 3A further illustrates a pull wire mount (160) placed proximally tothe compression tube mount (150). Similar to the compression tube mount(150), the pull wire mount (160) also has an elongated hollow body withan axial lumen (166) extending from one end (162) to the other end(164). The catheter shaft (12) is slidably disposed within the axiallumen (166) of the pull wire mount (160). As shown in FIG. 3A, the pullwire mount (160) also has a key slot (168) extending from its axiallumen (166) radially away to the exterior surface. The key slot (168) isconfigured to receive the proximal end of the pull wire (16). In someembodiment, the proximal end of the pull wire (16) is bonded to the keyslot (168) of the pull wire mount (160). According to some embodiment,the pull wire mount (160) is fixed to the middle handle shaft (110) sothat the pull wire mount (160) is prevented from rotating and movinglaterally relative to the middle handle shaft (110).

Now referring to FIG. 3B, the catheter shaft (12) extends proximallythrough the axial lumen (141) of the threaded rotator (140), the axiallumen (156) the compression tube mount (150), the axial lumen (166) ofthe pull wire mount (160), and then further extends proximally beyondthe outer handle shaft (100), thus outside of the control handleassembly (14). According to one embodiment of the present teachings, theproximal end of the shaft is used to insert a medical implant, or as theentrance for a RF wire.

Continue referring FIG. 3B, as described above, the catheter shaft (12)bonds to the compression tube mount (150) with the key on the cathetershaft (12) disposed within the key slot (158) of the compression tubemount (150). The proximal end of the pull wire (16) bonds to the pullwire mount (160). The threaded rotator (140) joins the compression tubemount (150), together they are position distal to the pull wire mount(160). As shown in FIG. 3B, the pull wire mount (160) is proximal to thecompression tube mount (150), and the threaded rotator (140) is distalto the compression tube mount (150) with the threaded proximal portion(144) next to the compression tube mount (150) and the unthreaded distalportion (142) outside of the outer handle shaft (100).

Continue referring to FIG. 3B, the pull wire mount (160), thecompression tube mount (150) and the threaded rotator (140) assembly areplaced inside the center lumen (116) of the middle handle shaft (110).As shown in FIG. 3B, the pull wire mount (160) is fixed to a locationinside the middle handle shaft (110). The compression tube mount (150)joins to the threaded rotator (140) forming an assembly which movesdistally or proximally. Such laterally movement is translated to thecatheter shaft (12) through the bonding between the catheter shaft (12)and the compression tube mount (150). The movement of the compressiontube mount (150) and the threaded proximal portion (144) of threadedrotator (140) assembly is limited inside the middle handle shaft (110).Although the threaded rotator (140) and compression tube assembly isconfigured to slide within the center lumen of the middle handle shaft(110), and thereby pulling or pushing the catheter shaft distally orproximally. The unthreaded distal portion (142) of the threaded rotator(140) extends distally outside of the middle handle shaft (110). Asteering knob (149) attaches to the distal portion (142) of the threadedrotator (140). The steering knob (149) can be used by a clinical controlto push, pull, and rotate the thread rotator.

Further referring to FIG. 3C, the thread follower (122) is placed insidethe thread follower retainer slot (118) on the middle handle shaft (110)with the bottom threads (124) facing the threads (144) of the threadedrotator (140). A set screw (120) is place inside the through hole (108)on the outer handle shaft (100). As illustrated in FIG. 3C, the setscrew (120) slightly protrudes beyond the interior slotted surface ofthe outer handle shaft (100). FIG. 3C illustrates the thread follower(122) centers under the set screw (120). As shown in FIG. 3C, the setscrew (120) presses on the first ball bearing (127), the first ballbearing (127) then compresses the spring (128), the spring (128) thenforces the second bear bearing (129) against the bottom of the hole. Thethread follower (122) then engages toward the threaded rotator (140).Threads (124) thereby engages the threads (144) of the threaded rotator(140).

Referring again to FIG. 3B, the middle handle shaft (110), with all theassembly inside its center lumen (116), is disposed inside the centerlumen (106) of the outer handle shaft (100). Two springs (107, 109),including a proximal spring (109) and a distal spring (107), are placedat each end of the middle handle shaft (110). These two springs (107,109), at their relaxed state, force the middle handle shaft (110) insidethe outer handle shaft (100) to its first position where the threadfollower (122) centers under the set screw (120) thereby allowing thethreads (124) of the thread follower (122) engages the threads (144) ofthe threaded rotator (140) as described above and illustrated in FIG.3C. When the middle handle shaft (110) is being pulled distally with aforce “F”, the distal spring is compressed, the first ball bearing (127)is freed from the set screw (120). As the first ball bearing enters thelongitudinal slot (105) on the interior surface (103) of the outerhandle shaft (100), the spring (108) relaxed, and the thread follower(122) then moves away from the thread rotator (140). Engagement betweenthreads (124, 144) is then released, and the middle handle shaft (110)is now in its second position where the thread rotator (140) and thecompression tube mount (150) assembly moves distally and proximally withlateral force without the constriction of the threads (124, 144)engagement, as illustrated in FIG. 3D. Once the pulling force “F” isreleased, the proximal spring recovers and pushes the middle handleassembly back to its first position as illustrated in FIG. 3B.

FIGS. 4A-4E illustrate the moving mechanism of the control handleassembly (14) in FIGS. 3A-3C. As shown in FIG. 4A, the middle handleshaft (110) is at its first position within the outer handle shaft (100)and the springs (107, 109) are in their relaxed state. In operation, theclinician holds the outer handle shaft (100) steady, and pullingsteering knob (149) distally. As illustrated in FIG. 4B, the first ballbearing (127) is released from the set screw (120), the spring (128)recovers to its relaxed state, the threads (124, 144) disengage fromeach other, the thread follower (122) floats, and the middle handleshaft (110) is now in its second position. While keep holding the outerhandle shaft (100) steady, the clinician can continue pull the steeringknob (149) distally, the threaded rotator (140) and compression tubemount (150) assembly slide laterally inside the middle handle shaft(110), as illustrated in FIG. 4C, and carrying catheter shaft (12) withit. The distal portion (22) of the catheter shaft (12) deflects as thedistance between the pull wire mount (160) and compression tube mount(150) changes. Thus such push-pull of the steering knob (149) leads to agross displacement of the distal portion (22) of the catheter shaft(12).

As the clinician releases the outer handle shaft (100), the springs(107, 109) recover and the middle handle shaft (110) resumes its firstposition within the outer handle shaft (12). The set screw (120) employsthe first ball bearing (127), and the thread follower (122) engages thethreaded rotator (140) as illustrated FIG. 4D. According to someembodiments, the threads engagement functions as a linear actuator andconverts the rotational motion of the threads into a linear motion. Atthis point, the clinician rotates the threaded rotator (140), and suchrotation motion is translated into a lateral movement by the threads(124, 144) engagement, thereby allows the threaded rotator (140) andcompression tube mount (150) assembly move laterally relative to thepull wire mount (160), as shown in FIG. 4E. Thus, such threadrotation-to-linear actuation leads to a precision displacement of thedistal portion (22) of the catheter shaft (12).

In one embodiment of the present teaching, as the threaded rotator (140)rotates 180°, the distal end (24) of the catheter shaft (12) displacesof 0.5 mm to 5 mm. In some embodiments, the precision displacement ofthe distal portion (22) of the catheter shaft (12) depends on the stepangle and pitch of the threads (124, 144) assembly. According to someembodiments, the thread (144) could have multiple starts, multiplepitches.

One skilled in the art should understand that, according to someembodiments, the design principle of the present teachings includes aquick linear motion by the control handle assembly to allow a grossdisplacement of the deflectable distal portion of the catheter shaft,and an automatic engagement of the thread mechanism allowing arotation-to-linear actuation imparts a precision displacement of thedeflectable distal portion of the catheter shaft. The exemplaryembodiments shown in FIGS. 3A-3D incorporate such principle. Theexemplary embodiments shown in FIGS. 4A-4D explains the workingmechanism of such principle. One skilled in the art should understandthat other design example could also be incorporate to embody suchprinciple.

FIGS. 5A-5C further illustrate another embodiment of present teaching.In the most part, this exemplary embodiment is similar to the exemplaryembodiment described above. For example, a catheter shaft (52) extendsthrough the center lumen (241) of a rotating cam (240), the center lumen(256) of the compression tube mount (250), and the center lumen (266) ofthe pull wire mount (260). The catheter shaft (52) extends furtherproximally outside of the control handle assembly (54). The pull wiremount (260) is proximal to the compression tube mount (250), and therotator cam (240) is distal to the compression tube mount (250). Similarto described above, catheter shaft (52) fixes to the compression tubemount (250) through a key slot-key assembly, preventing the cathetershaft (52) from rotating and moving laterally relative to thecompression tube mount (250). The proximal end of the pull wire alsofixes to the pull wire mount (260).

Unlike what has been described above, in this exemplary embodiment, asshown in FIG. 5C, the rotating cam (240) has an enlarged distal portion(242) and a smaller proximal portion (246) with a flange (245) dividingthe two portions. A distal knob (249) joins the distal portion (242) ofthe rotating cam (240). The distal knob (249) also has a center lumenallowing the catheter shaft (52) to extend through. A centering bushing(230) also rides over the distal portion of the rotating cam (240) withtwo centering springs (207, 209) at each end of the centering bushing(230). As shown in FIG. 5B, the distal knob (249) is distal to thedistal spring (207), and the distal spring (207) is distal to thecentering bushing (230), and the centering bushing (230) is distal tothe proximal spring (209). According to one embodiment, the centeringbushing (230) fixes to the distal portion (242) of the rotating cam(240) in such way that the centering bushing (230) is prevented fromrotating relative to the rotating cam (240), while allowed to movelongitudinally relative to the rotating cam (240).

Further referring to FIG. 5B, unlike exemplary embodiment described inreference to FIGS. 3A-3D, the rotating cam (240) has no threads.Instead, a thread follower (222) positions over a ridge (232) onproximal portion (246) of the rotating cam (240). Similar to what hasbeen described in reference to FIG. 3B, a hole (226) housing a secondball bearing (229) inside and a spring (228) trapped in between of afirst ball bearing (227) and the second ball bearing (229). The threadfollower (222) also has a threaded surface facing radially away from therotating cam (240). The threads (224) on the thread follower (222) isconfigured to engage the threads (244) on the interior surface of theouter handle shaft (200) as described below.

FIG. 5C, further illustrates a middle handle shaft (210) has a centerlumen (216) configured to house the rotating cam (240). The middlehandle shaft (210) has a through hole (208) extends from its centerlumen to its exterior surface, configured to house the thread follower(222). As shown in FIG. 5A, the middle handle shaft (210) joins thecompression tube mount (250) at its proximal portion. According to oneembodiment of the present teaching, the compression tube mount (250)joins the middle handle shaft (210) in such way that allows the middlehandle shaft (210) rotate independently from the compression tube mount(250), while prevent the middle handle shaft (210) from move laterallyrelative to the compression tube mount (250).

Further referring to FIG. 5A, the outer handle shaft (200) has a centerlumen (206) configured to house the pull wire mount (260), thecompression tube mount (250) and the middle handle shaft (210) carryingrotating cam (240) and the distal knob (249). The pull wire mount fixesto the outer handle shaft (200), and the distal knob (249) extendsdistally outside of the center lumen (206) of the distal knob (249).

FIG. 5A illustrates one embodiment of the present teaching where themiddle handle shaft (210) is in its first position. As shown in thefigure, centering springs (207, 209) are relaxed, the first ball bearing(227) centers over the ridge (232) on the proximal portion (246) of therotating cam (240). As such, the first ball bearing compresses thespring (228) and the second ball bearing (229), the thread follower(222) thereby forced toward the interior surface of the outer handleshaft (200). Threads (224, 244) then engage each other. At this point,by holding knob (249) steady, a clinician can then rotates the outerhandle shaft (200). Since the rotating cam (240) joins the middle handleshaft (210), and the middle handle shaft (210) joins the compressiontube mount (250), the threads (224, 244) rotation allows the middlehandle shaft (210) and compression tube mount (250) assembly movelaterally relative to the pull wire mount (260). Thus, such threadrotation-to-linear actuation leads to a precision displacement of thedistal portion (52) of the catheter shaft (52).

FIG. 5D illustrates one embodiment of the present teaching where themiddle handle shaft (210) is in its second position. As shown in thefigure, as the knob (249) being pulled distally, the proximal spring(209) compresses, and the rotating cam (240) being pulled distally. Theridge (232) on the proximal portion (246) of the rotating cam (240)moves distally relative to the first ball bearing (227). FIG. 5D showsthat first ball bearing free from the ridge (232), the spring (228) inbetween the two ball bearing (227, 229) relaxes. Such relaxation carriesthe thread follower (222) moving away from the interior threaded surfaceof the outer handle shaft (200). Threads (224, 244) then disengage eachother. At this point, by holding outer handle shaft (200) steady, aclinician call can push the knob (249) distally, thereby changing thedistance between the pull wire mount (260) and compression tube mount(250) and leading the distal portion (52) of the catheter shaft (52)deflect. Thus such push-pull of the knob (249) leads to a grossdisplacement of the distal portion (52) of the catheter shaft (52).

As the clinician releases the outer handle shaft (100), the springs(107, 109) recover and the middle handle shaft (110) resumes its firstposition within the outer handle shaft (12). The set screw (120) employsthe first ball bearing (127), and the thread follower (122) engages thethreaded rotator (140) as illustrated FIG. 4D. According to someembodiments, the threads engagement functions as a linear actuator andconverts the rotational motion of the threads into a linear motion. Atthis point, the clinician rotates the threaded rotator (140), and suchrotation motion is translated into a lateral movement by the threads(124, 144) engagement, thereby allows the threaded rotator (140) andcompression tube mount (150) assembly move laterally relative to thepull wire mount (160), as shown in FIG. 4E. Thus, such threadrotation-to-linear actuation leads to a precision displacement of thedistal portion (22) of the catheter shaft (12).

As the clinician releases the force applied to the knob (249), thespring (209) recovers and the middle handle shaft (210) resumes itsfirst position within the outer handle shaft (200). The thread follower(222) repositions over a ridge (232) on proximal portion (246) of therotating cam (240). The spring (228) compressed and the threads (224,244) engage each other as illustrated FIG. 5D. According to someembodiments, the threads engagement functions as a linear actuator andconverts the rotational motion of the threads into a linear motion. Atthis point, the clinician rotates the rotating cam (240), and suchrotation motion is translated into a lateral movement by the threads(224, 244) engagement, thereby allows the compression tube mount (250)move laterally relative to the pull wire mount (260). Thus, such threadrotation-to-linear actuation leads to a precision displacement of thedistal portion of the catheter shaft (52).

According to some embodiments, although exemplary embodiment has beendescribed above in order to explain the present invention, one skilledin the art should understand, design details could be replaced toachieve the same function. For example, set screw (120) described inreference to FIGS. 3A-3D could be place with a ridge design. Proximaland distal springs (107, 109, 207, and 209) could have different size,shape, and recover force. Such design variation should be considered aswithin the scope of present invention.

Exemplary embodiment shown in FIG. 5A-5D also accomplishes the abovedescribed design principle of the present teaching. That is, a quicklinear motion by the control handle assembly to allow a grossdisplacement of the deflectable distal portion of the catheter shaft,and an automatic engagement of the thread mechanism allowing arotation-to-linear actuation imparts a precision displacement of thedeflectable distal portion of the catheter shaft. Thus, those skilled inthe art should understand that the exemplary embodiments described abovecould be modified in various execution while still achieve the samedesign principle.

Various embodiments have been illustrated and described herein by way ofexamples, and one of ordinary skill in the art would recognize thatvariations can be made without departing from the spirit and scope ofthe present teachings. The present teachings are capable of otherembodiments or of being practiced or carried out in various other ways.Also, it is to be understood that the phraseology and terminologyemployed herein is for the purpose of description and should not beregarded as limiting.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this present teachings belong. Methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present teachings. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and notintended to be limiting.

I claim:
 1. A catheter control mechanism comprising: a first shaft, anda second shaft, wherein the first shaft defines an interior lumen,wherein the second shaft is positioned inside the interior lumen of thefirst shaft; and wherein the second shaft has a first position whereinthe second shaft engages an interior surface of the first shaft via athread engagement, and a second position wherein the second shaft moveslaterally without the restriction of the thread engagement.
 2. Thecatheter control mechanism of claim 1 further comprising a linearactuator, wherein the linear actuator comprises: a threaded rotator, anda thread follower with pairing threads; and wherein the linear actuatoris configured to convert the rotational motion of the threads into arelative linear motion of the second shaft and the first shaft.
 3. Thecatheter control mechanism of claim 1 further comprising two centeringsprings, wherein each centering spring is placed on each side of thesecond shaft inside the interior lumen of the first shaft, and whereinwhen the centering spring is in its relaxed state, the second shaft incentered within the interior lumen of the first shaft.
 4. The cathetercontrol mechanism of claim 1 further comprising a thread engagementmechanism, wherein the thread engagement mechanism comprises a threadfollower that engages a thread inside the interior luminal surface ofthe first shaft.
 5. The thread engagement mechanism of claim 4 furthercomprising a spring, wherein when the spring is compressed, the threadfollower engages the thread inside the interior luminal surface of thefirst shaft; and when the spring relaxes, the thread follower disengagesfrom the threads inside the interior luminal surface of the first shaft.6. The catheter control mechanism according to claim 1 wherein at leasta distal portion of the second shaft defines a center lumen adapted toreceive a catheter.
 7. The catheter control mechanism according to claim1 wherein the thread engagement comprises an external thread defined bythe second shaft engaging an internal thread defined by the first shaft,within the lumen.
 8. An apparatus for use with a body of a subject, theapparatus comprising: a catheter, configured to be transluminallyadvanced into the body; and an extracorporeal catheter controlmechanism, coupled to a proximal portion of the catheter, andcomprising: a first shaft defining a lumen having an engagement zone;and a second shaft disposed within the lumen, wherein the extracorporealcatheter control mechanism is reversibly transitionable between anengaged state and a disengaged state, such that: in the engaged state,the second shaft is threadedly engaged with the first shaft, and ismoveable axially though the engagement zone of the lumen via rotation ofthe second shaft with respect to the first shaft, and in the disengagedstate, the second shaft is moveable axially through the engagement zoneof the lumen independently of rotation of the second shaft with respectto the first shaft.
 9. The apparatus according to claim 8 furthercomprising a pull wire having a first end attached to a distal end ofthe catheter, and a second end coupled to the second shaft, such thatmovement of the second shaft with respect to first shaft deflects thedistal end of the catheter by tensioning a distal portion of the pullwire.
 10. The apparatus according to claim 8 wherein the second shaftdefines an external thread that, in the engaged state, engages with thefirst shaft within the engagement zone.
 11. The apparatus according toclaim 10 further comprising a thread follower coupled to the first shaftin the engagement zone, the thread follower defining a threaded surface,and being reversibly movable between: an engaged position in which thethreaded surface is threadedly engaged with the external thread, suchthat the catheter control mechanism is in the engaged state, and adisengaged position in which the threaded surface is disengaged from theexternal thread, such that the catheter control mechanism is in thedisengaged state.
 12. The apparatus according to claim 11 wherein thethread follower comprises: a bearing; and a spring, functionally coupledto the bearing.
 13. The apparatus according to claim 12 furthercomprising an outer shaft, the first shaft being disposed within theouter shaft, and the catheter control mechanism being configured suchthat: in a first location of the first shaft with respect to the outershaft, the bearing holds the threaded surface in engagement with theexternal thread, thereby placing the thread follower in the engagedposition, and in a second location of the first shaft with respect tothe outer shaft, the spring pushes the bearing and the threaded surfaceaway from the external thread, such that the thread follower is in thedisengaged position.
 14. The apparatus according to claim 13, wherein:the bearing is a first bearing, the thread follower further comprises asecond bearing, the spring is functionally disposed between the firstbearing and the second bearing, and in the second location of the firstshaft with respect to the outer shaft, the spring pushes the firstbearing and the threaded surface away from the external thread bypushing the second bearing against the external thread.
 15. Theapparatus according to claim 14, wherein the second bearing is a ballbearing.
 16. The apparatus according to claim 13, wherein the cathetercontrol mechanism further comprises a steering knob coupled to a distalportion of the second shaft.
 17. The apparatus according to claim 16,wherein, in the engaged state, rotation of the steering knob withrespect to the outer shaft moves the second shaft axially though theengagement zone of the lumen by rotating the second shaft with respectto the first shaft.
 18. The apparatus according to claim 16, whereinmovement of the steering knob distally with respect to the outer shafttransitions the first shaft from the first location to the secondlocation with respect to the outer shaft, such that the catheter controlmechanism transitions from the engaged state to the disengaged state.19. The apparatus according to claim 18, further comprising a distalspring disposed distally from the first shaft in a manner in which: themovement of the steering knob distally with respect to the outer shaftsuch that the catheter control mechanism transitions from the engagedstate to the disengaged state, compresses the distal spring, in thedisengaged state, the distal spring is configured to return the firstshaft to the first location with respect to the outer shaft, therebyreturning the catheter control mechanism to the engaged state.
 20. Theapparatus according to claim 16, wherein: in the engaged state of thecatheter control mechanism, axial movement of the steering knob withrespect to the outer shaft axially moves the first shaft and the secondshaft with respect to the outer shaft, and in the disengaged state ofthe catheter control mechanism, axial movement of the steering knob withrespect to the outer shaft moves the second shaft with respect to thefirst shaft.
 21. The apparatus according to claim 16 further comprisinga pull wire having a first end attached to a distal end of the catheter,and a second end coupled to the catheter control mechanism, such thatmovement of the steering knob distally with respect to the outer shaftdeflects a distal portion of the catheter by tensioning a distal portionof the pull wire.